Projector lamp filament support



Sept. 30, 1969 c. c. BLAIR, JR., ETAL 3,470,413

PROJECTOR LAMP FILAMENT SUP PORT Filed April 28. 1966 R RD E. SMITH CHESTER C. BLAIR JR.

I NVEN'I'ORS BY CW AT TORN Y United States Patent US. Cl. 313--331 6 Claims ABSTRACT OF THE DISCLOSURE A projector lamp in which each of the end segments of a coiled-coil filament is threaded over a substantially L-shaped support member which is in turn supported by and from a side rod of the mount framework.

This invention relates to incandescent electric lamps and more particularly to a filament support arrangement for projector lamps.

Over the years, one of the problems which has always been associated with the manufacture of projector lamps has been the means employed to support the filament. One of the arrangements more commonly employed, particularly with high wattage projector lamps, has been the use of short segments of wires, commonly called spuds, over one end of which an end segment of a projection lamp filament would be wound, the other end of the spud being welded to a side rod. However, with lamps of lower wattages, this type of arrangement is not satisfactory because the filament is quite limp and flimsy and does not have sutficient body and weight relative to the spud to permit this type of supporting arrangement.

In view of the foregoing, one of the principal objects of this invention is to provide a simple, satisfactory arrangement for supporting projector lamp filaments, particularly those of low Wattages.

This and other objects, advantages and features are attained, in accordance with the principles of this invention, by threading each end segment of a coiled-coil filament over a substantially L-shaped support member which is supported by and from a side rod of the mount framework. Each end segment is threaded over its support member until the first lighted filament segment and the loop therebetween have been properly positioned. The mount is then flashed, thus setting the tungsten structure of the end segments so that they then hold their position.

In the specific embodiment of the invention illustrated in the accompanying drawing, FIGURE 1 is a front elevational view of a projector lamp in which the filament is supported in the manner taught by this invention.

FIGURE 2 is a side elevational view of the lamp of FIGURE 1.

FIGURE 3 is an enlarged detail of the filament-supporting arrangement of the invention.

Referring now to the drawing, particularly FIGS. 1 and 2 thereof, the projector lamp illustrated therein comprises an hermetically sealed, substantially tubular glass envelope 1 having a coating 3 of an enamel glaze at one end and a metal base 5 at the other end. A lamp ori-. enting post 7 and lead-in pins 9, 10, 11 and 12 depend from the bottom of the base 5. Lead-in pins 9, 10', 11 and 12 extend into the inside of the lamp envelope 1 and support the mount structure therein. The mount structure comprises a multi-segment filament 15, each segment having a loop 16 at each end thereof, said loops providing the means whereby the filament segments are hung on upper filament support hooks 21 and stretched over lower "ice filament support hooks 23. The hOOks 21 depend from a glass rod or bridge 25 which is in turn mounted on spuds 27 welded to side rods 19. The hooks 23 are upstanding on a glass rod or bridge 29 which is in turn supported by brackets 31 welded to side rods 19. The side rods 19 are welded to the inner ends of lead-in pins 9 and 111. A brace 33 connects one of the side rods 19 to dummy pin 11 to aid in stabilizing the mount structure. A fuse wire (not shown) covered by a sleeve of fiber glass tubing 37, is connected across pins 10 and 12.

The manner in which each end segment 13 of the multi-segment filament 15 is supported is illustrated in detail in FIG. 3. Each end segment 13 is threaded over leg a and onto leg b of a substantially L-shaped insert 17, said insert being welded at the end of leg b thereof to one of the side rods 19. It will be noted that a loop 16 connects end segment 13 to the first lighted segment 14 of the multi-segment filament 15. It will be noted from an examination of FIGS. 1 and 2 that the legs a of the L-shaped inserts 17 over which the end segments 13 of the filament 15 are threaded are oriented differently, one being directed downwardly and the other upwardly.

While there has been shown and described what is at present considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention as defined by the appended claims.

What we claim is:

1. An electric lamp comprising: an hermetically sealed, light-transmitting envelope; a mount structure including a pair of side rods and a multi-segment filament supported in said envelope, said multi-segment filament comprising a plurality of lighted segments and a pair of end segments, said end segments being spaced from and connected to their respective adjacent lighted segments by a loop; and an insert attached to each of said side rods, each of said end segments being threaded onto one of said inserts.

2. The combination of claim 1 in which each insert is a substantially L-shaped member having a horizontal leg and a vertical leg, and each said end segment is threaded over said vertical leg and onto said horizontal leg.

3. The combination of claim 1 in which said inserts are located in different horizontal planes.

4. The combination of claim 2 in which said inserts are located in different horizontal planes.

5. The combination of claim 2 in which the vertical legs of said inserts point in opposite directions.

6. The combination of claim 2 in which said inserts are located in different horizontal planes and the vertical legs thereof point in opposite directions.

References Cited UNITED STATES PATENTS 1,637,034 7/1927 Bergmans 313-271 3,069,582 12/1962 Reilly et al 313--271 2,134,574 10/1938 Dinkle 3l3315 X 2,848,642 8/1958 Wisco et a1. 313332 X 3,025,424 3/1962 Wiley et al 313--316 X 3,221,202 11/1965 McLintic 313-344 X JOHN W. HUCK-ERT, Primary Examiner ANDREW J. JAMES, Assistant Examiner US. Cl. X.R. 

